Technical Field
The present invention relates to a three dimensional mold object manufacturing apparatus, a method for manufacturing a three dimensional mold object, and a three dimensional mold object.
Related Art
A technique is known where a three dimensional mold object is molded by forming a powder layer (a unit layer) using particles and the powder layers are layered. With this technique, the three dimensional mold object is molded by the following operations being repeated. First, a powder layer is formed by thinly laying powder with a uniform thickness and the powder is selectively bonded only at desired portions of the powder layer. As a result, a member with a thin plate shape (referred to below as a “cross sectional member”) is formed at a portion where the powder is bonded to itself. After this, on this powder layer, another powder layer is thinly formed and the powder is selectively bonded only at desired portions. As a result, a new cross sectional member is formed with the powder layer which is newly formed. At this time, the cross sectional member which is newly formed is also bonded with the cross sectional member which was previously formed. By repeating these operations, it is possible to form a three dimensional mold object by layering the cross sectional members with the thin plate shape one layer at a time.
There are problems with this technique such as that, since the powder layer with a smaller thickness (for example, a powder layer with a thickness of several hundred μm or less) is formed using the powder, dimensional precision of the three dimensional mold object which is obtained is reduced and significant defects are generated such as missing portions or the like in the three dimensional mold object which is obtained in a case where there are bulges due to foreign matter or the like on the powder layer even when the size of the three dimensional mold object is relatively small.
In order to solve this problem, a method is proposed where bulges are removed using a processing means (a removing means) which is provided with a milling head (for example, refer to Japanese Unexamined Patent Application Publication No. 2004-277881). However, productivity of the three dimensional mold object is reduced due to this method. In particular, in a case where there are numerous bulges, productivity of the three dimensional mold object is remarkably reduced since it is necessary for the bulges to be removed individually. In addition, it is necessary to carry out planarizing again since removing of the bulges is accompanied with disturbing of the layer and this is a further cause of productivity of the three dimensional mold object being reduced.